A novel rat model of temporomandibular disorder with improved face and construct validities.

Autor: Phero A; Department of Anesthesiology, University of Utah School of Medicine, 383 Colorow Dr., Research Park, Salt Lake City, UT 84108, United States of America., Ferrari LF; Department of Anesthesiology, University of Utah School of Medicine, 383 Colorow Dr., Research Park, Salt Lake City, UT 84108, United States of America. Electronic address: luiz.ferrari@utah.edu., Taylor NE; Department of Anesthesiology, University of Utah School of Medicine, 30 North 1900 East, SOM 3C444, Salt Lake City, UT 84132-2304, United States of America. Electronic address: norman.taylor@hsc.utah.edu.
Jazyk: angličtina
Zdroj: Life sciences [Life Sci] 2021 Dec 01; Vol. 286, pp. 120023. Date of Electronic Publication: 2021 Oct 07.
DOI: 10.1016/j.lfs.2021.120023
Abstrakt: Aims: Temporomandibular disorders are a cluster of orofacial conditions that are characterized by pain in the temporomandibular joint (TMJ) and surrounding muscles/tissues. Animal models of painful temporomandibular dysfunction (TMD) are valuable tools to investigate the mechanisms responsible for symptomatic temporomandibular joint and associated structures disorders. We tested the hypothesis that a predisposing and a precipitating factor are required to produce painful TMD in rats, using the ratgnawmeter, a device that determines temporomandibular pain based on the time taken for the rat to chew through two obstacles.
Materials and Methods: Increased time in the ratgnawmeter correlated with nociceptive behaviors produced by TMJ injection of formalin (2.5%), confirming chewing time as an index of painful TMD. Rats exposed only to predisposing factors, carrageenan-induced TMJ inflammation or sustained inhibition of the catechol-O-methyltransferase (COMT) enzyme by OR-486, showed no changes in chewing time. However, when combined with a precipitating event, i.e., exaggerated mouth opening produced by daily 1-h jaw extension for 7 consecutive days, robust function impairment was produced.
Key Findings: These results validate the ratgnawmeter as an efficient method to evaluate functional TMD pain by evaluating chewing time, and this protocol as a model with face and construct validities to investigate symptomatic TMD mechanisms.
Significance: This study suggests that a predisposition factor must be present in order for an insult to the temporomandibular system to produce painful dysfunction. The need for a combined contribution of these factors might explain why not all patients experiencing traumatic events, such as exaggerated mouth opening, develop TMDs.
(Copyright © 2021 Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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